package server;

import mapper.Mapper;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * Minicat的主类
 */
public class Bootstrap {

    /**
     * 定义socket监听的端口号
     */
    private int port = 8080;
    private Map<String, HttpServlet> servletMap = new HashMap<String, HttpServlet>();
    private Map<String, Object> serverMap = new HashMap<String, Object>();

    private Mapper mapper = Mapper.instance();

    /**
     * Minicat 的程序启动入口
     *
     * @param args
     */
    public static void main(String[] args) {
        Bootstrap bootstrap = new Bootstrap();
        try {
            // 启动Minicat
            bootstrap.start();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    public int getPort() {
        String port = mapper.getMappedHost().getPort();
        if (port != null) return Integer.valueOf(port);
        return this.port;
    }


    /**
     * Minicat启动需要初始化展开的一些操作
     */
    public void start() throws Exception {
        // 加载的配置
        load();

        // 定义一个线程池
        int corePoolSize = 10;
        int maximumPoolSize = 50;
        long keepAliveTime = 100L;
        TimeUnit unit = TimeUnit.SECONDS;
        BlockingQueue<Runnable> workQueue = new ArrayBlockingQueue<>(50);
        ThreadFactory threadFactory = Executors.defaultThreadFactory();
        RejectedExecutionHandler handler = new ThreadPoolExecutor.AbortPolicy();


        ThreadPoolExecutor threadPoolExecutor = new ThreadPoolExecutor(
                corePoolSize,
                maximumPoolSize,
                keepAliveTime,
                unit,
                workQueue,
                threadFactory,
                handler
        );





        /*
            完成Minicat 1.0版本
            需求：浏览器请求http://localhost:8080,返回一个固定的字符串到页面"Hello Minicat!"
         */
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("=====>>>Minicat start on port：" + port);

        /*while(true) {
            Socket socket = serverSocket.accept();
            // 有了socket，接收到请求，获取输出流
            OutputStream outputStream = socket.getOutputStream();
            String data = "Hello Minicat!";
            String responseText = HttpProtocolUtil.getHttpHeader200(data.getBytes().length) + data;
            outputStream.write(responseText.getBytes());
            socket.close();
        }*/


        /**
         * 完成Minicat 2.0版本
         * 需求：封装Request和Response对象，返回html静态资源文件
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            response.outputHtml(request.getUrl());
            socket.close();

        }*/


        /**
         * 完成Minicat 3.0版本
         * 需求：可以请求动态资源（Servlet）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            InputStream inputStream = socket.getInputStream();

            // 封装Request对象和Response对象
            Request request = new Request(inputStream);
            Response response = new Response(socket.getOutputStream());

            // 静态资源处理
            if(servletMap.get(request.getUrl()) == null) {
                response.outputHtml(request.getUrl());
            }else{
                // 动态资源servlet请求
                HttpServlet httpServlet = servletMap.get(request.getUrl());
                httpServlet.service(request,response);
            }

            socket.close();

        }
*/

        /*
            多线程改造（不使用线程池）
         */
        /*while(true) {
            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket,servletMap);
            requestProcessor.start();
        }*/


        System.out.println("=========>>>>>>使用线程池进行多线程改造");
        /*
            多线程改造（使用线程池）
         */
        while (true) {

            Socket socket = serverSocket.accept();
            RequestProcessor requestProcessor = new RequestProcessor(socket, servletMap, mapper);
            //requestProcessor.start();
            threadPoolExecutor.execute(requestProcessor);
        }


    }

    private void load() {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("server.xml");
        SAXReader saxReader = new SAXReader();

        try {
            Document document = saxReader.read(resourceAsStream);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//Server");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element = selectNodes.get(i);
                List<Element> ServiceNodes = element.selectNodes("//Service");
                for (int j = 0; j < ServiceNodes.size(); j++) {
                    Element ConnectorElement = (Element) element.selectSingleNode("//Connector");
                    String port = ConnectorElement.attribute("port").getStringValue();

                    List<Element> EngineNodes = element.selectNodes("//Engine");
                    for (int k = 0; k < EngineNodes.size(); k++) {
                        Element HostElement = (Element) element.selectSingleNode("//Host");
                        String host = HostElement.attribute("name").getStringValue();

                        String appBase = HostElement.attribute("appBase").getStringValue();

                        loadProject(host, port, appBase);
                    }
                }

            }


        } catch (DocumentException e) {
            e.printStackTrace();
        }

    }
    // webapps 下面的 项目 内容
    void loadProject(String host, String port, String appBase) {
        File projectFiles = new File(appBase);
        if (!projectFiles.exists() || projectFiles.isFile()) {
            return;
        }
        // 获取所有项目
        File[] files = projectFiles.listFiles();
        if (files.length < 1) {
            return;
        }
        for (File f : files) {
            String projectName = f.getName();
            String projectPath = f.getPath().replace("\\", "/");
            String webxmlPath = projectPath + "/web.xml";
            String classPath = projectPath + "";
            // 加载解析相关的配置，web.xml
            loadServlet(host, port, projectName, projectPath, webxmlPath, classPath);

        }
    }

    /**
     * 加载解析web.xml，初始化Servlet
     */
    private void loadServlet(String host, String port, String projectName, String projectPath, String webxmlPath, String classPath) {
//        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream("web.xml");
        MyClassLoader webappClassLoader = new MyClassLoader();

        SAXReader saxReader = new SAXReader();
        try {
            // web.xml
            Document document = saxReader.read(webxmlPath);
            Element rootElement = document.getRootElement();

            List<Element> selectNodes = rootElement.selectNodes("//servlet");
            for (int i = 0; i < selectNodes.size(); i++) {
                Element element = selectNodes.get(i);
                // <servlet-name>lagou</servlet-name>
                Element servletnameElement = (Element) element.selectSingleNode("servlet-name");
                String servletName = servletnameElement.getStringValue();
                // <servlet-class>server.LagouServlet</servlet-class>
                Element servletclassElement = (Element) element.selectSingleNode("servlet-class");
                String servletClass = servletclassElement.getStringValue();

                //根据servletClass生成实例
                Class clz = webappClassLoader.findClass(classPath, servletClass);

                // 根据servlet-name的值找到url-pattern
                Element servletMapping = (Element) rootElement.selectSingleNode("/web-app/servlet-mapping[servlet-name='" + servletName + "']");
                // /lagou
                String urlPattern = servletMapping.selectSingleNode("url-pattern").getStringValue();
//                servletMap.put(urlPattern, (HttpServlet) Class.forName(servletClass).newInstance());
                // server.xml  项目的信息 项目中servlet的信息
                mapper.add(host, port, projectName, projectPath, webxmlPath, classPath, urlPattern, (HttpServlet) clz.newInstance());
            }


        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        } catch (InstantiationException e) {
            e.printStackTrace();
        }

    }
}
